EP0192142A1
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EP
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Charge transfer device
Assignee: Toshiba Corp
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Filing: 1986-02-07
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Granted: —
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Expires: 2006-02-07
Abstract
Abstract A transfer channel (13) for transferring charges and a floating diffusion region (33) are formed in a semiconductor substrate. The region (33) receives the charges transferred through the transfer channel (13) and stores them therein. A transfer gates (25. 27) are formed above the transfer channel (131. An output gate electrode (31) is formed above the end portion of the transfer channel (13, 15, 17). The electrode (31) controls the flow of charges from the transfer channel (13, 15.17) to the floating diffusion region (33). An output section (39) is provided for producing a voltage signal corresponding to the amount of charges stored in the floating diffusion region (33). The output gate electrode (31) is connected to the transfer substrate (11) to keep small the output impedance of a circuit for supplying a fixed potential to the output gate electrode (31). Therefore, the product of a capacitance of the gate electrode (31) AC coupled to ground and the output impedance of that circuit is very small. With the very small impedance, the noise induced into the output signal (VOUT) by the clock signals (φ1, φ2) is damped for a short period of time. The output signal (VOUT) is littled influenced by the noise, and therefore the charge transfer device is operable at a high speed.
Inventors
- 👤 Makoto c/o Patent Division Monoi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 11:26
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/28; G11C19/282; G11C19/285; H; H10; H10D; H10D44/00; H10D44/40; H10D44/45; H10D44/454
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
223 words
A charge transfer device comprising: a semiconductor region (13) for transferring charges; transfer electrodes (25, 27), provided above said semiconductor region (13), for receiving a plurality of clock signals (#1, φ2) to control the transfer and storage of charges in said semiconductor region (13, 15, 17); a floating diffusion region (33) which receives and stores the charges transferred through said semiconductor region (13, 15, 17); an output gate electrode (31), formed above the end portion of said semiconductor region (13, 15, 17), and for applying a predetermined potential to the end portion of said semiconductor region (13, 15, 17), thereby to control the flow of charges from said semiconductor region (13, 15, 17) to said floating diffusion region (33); power source means for applying a predetermined potential to said output gate electrode (31); and an output section (39) for producing a voltage signal corresponding to the amount of charges stoned in said floating diffusion region (33), characterized in that the product of a capacitance of said output gate electrode (31) AC coupled to ground and the output impedance of said power source means is determined, allowing for a signal period of said voltage signal and a damping period of the noise induced to said output signal by said clock signals, and is smaller than a value tolerable for guaranteeing a normal system operation.
Claim 2
Dependent Claim
223 words
A charge transfer device comprising: a semiconductor region (13) for transferring charges; transfer electrodes (25, 27), provided above said semiconductor region (13), for receiving a plurality of clock signals (#1, φ2) to control the transfer and storage of charges in said semiconductor region (13, 15, 17); a floating diffusion region (33) which receives and stores the charges transferred through said semiconductor region (13, 15, 17); an output gate electrode (31), formed above the end portion of said semiconductor region (13, 15, 17), and for applying a predetermined potential to the end portion of said semiconductor region (13, 15, 17), thereby to control the flow of charges from said semiconductor region (13, 15, 17) to said floating diffusion region (33); power source means for applying a predetermined potential to said output gate electrode (31); and an output section (39) for producing a voltage signal corresponding to the amount of charges stoned in said floating diffusion region (33), characterized in that the product of a capacitance of said output gate electrode (31) AC coupled to ground and the output impedance of said power source means is determined, allowing for a signal period of said voltage signal and a damping period of the noise induced to said output signal by said clock signals, and is smaller than a value tolerable for guaranteeing a normal system operation.
Claim 3
Dependent Claim
57 words
A charge transfer device according to claim 1, characterized in that said semiconductor region (13, 15, 17) is formed in a semiconductor substrate of the conductivity type different from that of said semiconductor region (13, 15, 17), and said power source means is a means for connecting said output gate electrode (31) to said semiconductor substrate (11).
Claim 4
Dependent Claim
81 words
A charge transfer device according to claim 1, characterized in that said semiconductor region (13, 15, 17) is formed in a semiconductor well of the conductivity type different from that of said semiconductor region (13, 15, 17); said semiconductor well (53) is formed in a semiconductor substrate (51) of the same conductivity type as that of said semiconductor region (13, 15, 17); said power source means is a means for connecting said output gate electrode (31) to said semiconductor well (53).
Claim 5
Dependent Claim
24 words
A charge transfer device according to claim 1, characterized in that said power source means applies ground potential to said output gate electrode (31).
Claim 6
Dependent Claim
116 words
A charge transfer device according to claim 1, characterized in that said semiconductor region (13) is so formed that the potential under the final stage transfer electrode (27) is deeper at least two steps successively in the direction of charge transfer, and that the potential under said output gate electrode (31) is deeper than the potential at the final stage in a potential distribution under said final stage transfer electrode (27) according to a potential level of said clock signal supplied to said final stage transfer electrode (27), to control charges in said semiconductor region to go over the potential barrier of said output gate electrode (31) and to flow into said floating diffusion region (33).
Claim 7
Dependent Claim
134 words
A charge transfer device according to claim 5, characterized in that said semiconductor region has a first region (19) under said final stage transfer electrode (27), said first reaion (19) having the same conductivity type as that of said semiconductor region (13) and an impurity concentration lower than that of said semiconductor region (13), and further has, in the charge transfer direction, a second region (21) in contact with said first region (19), said second region (21) having the same conductivity type as that of said first region (19) and an impurity concentration higher than that of said first region (19), but lower than that of said semiconductor region (13), and an impurity concentration at the region (29) under said output gate electrode (31) is substantially equal to that of said semiconductor region (13).
Claim 8
Dependent Claim
124 words
A charge transfer device according to claim 5, characterized in that said semiconductor region has a first region (13) under said final stage transfer electrode (27), said first region (15) having the same conductivity type as that of said semiconductor region (13) and a lower impurity concentration than that of said semiconductor region (13), and further has, in the charge transfer direction, a second region (17) in contact with said first region (15), said second region (21) having the same conductivity type as that of said semiconductor region (13) and an impurity concentration substantially equal to that of said semiconductor region (13), and an impurity concentration at the region (29) under said transfer electrode (31) is higher than that of said semiconductor region (13).
Claim 9
Dependent Claim
129 words
A charge transfer device according to claim 5, characterized in that said semiconductor region has, under said final stage transfer electrode (27), a first region (19) of an impurity concentration than that of said semiconductor region (13), and further has, in the charge transfer direction, a second region (17) in contact with said first region (15), said second region having an impurity concentration substantially equal to that of said semiconductor region (13), and an impurity concentration of the region (29) under said output gate electrode (31) is substantially equal to that of said semiconductor region (13), and a distance between said transfer electrodes (25, 27) and said semiconductor region (13) is shorter than a distance between said output gate electrode (31) and the surface of said semiconductor region (13).
References Cited (Backward Citations)
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